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There are two positions available.
These positions are no longer available

1. EPSRC PhD Studentship from October 2006 (no longer available)

2. EST PhD Studentship from October 2006 (no longer available)



1. EPSRC PhD Studentship from October 2006 (closed)

COMPUTER SIMULATION OF AQUEOUS RADICAL OXYGEN SPECIES

The species produced by the reduction of dioxygen O2 (or equivalently the oxidation of water H2O) are among the most reactive aqueous solutes known. The most aggressive is the hydroxyl radical HO*, followed by the superoxide O2- and peroxyl HO2* radicals. Also the hydrogen peroxide molecule H2O2, while not a radical, is counted among the reactive oxygen species (ROS) as is O2 itself (in particular the singlet spin isomer). The rich chemistry of ROS seems an attractive target for density functional theory (DFT) based molecular dynamics simulation (Car-Parrinello) as the reactions are fast and the reactants relatively small. It is also a very important area of applied chemistry involving key questions in radiation chemistry and the biochemistry of respiration. Unfortunately the standard DFT methods used in Car-Parrinello simulation fail for these radicals (errors in relative energies can be an eV or more). An extension of the DFT scheme is needed.
The aim of the project is to address these problems exploiting the methods we have developed in the context of a series of Car-Parrinello simulation studies of redox reactions in solution using less reactive species as model systems (transition-metal complexes [1,2], conjugated organic molecules [3]). Central in our approach is an efficient scheme for the computation of redox potentials based on the Marcus theory of electron transfer. This method provides us with a direct probe of the reactivity of radicals in terms of reaction, reorganization and activation free energies, which will be crucial for the validation and further development of a DFT scheme for treating radicals we have recently proposed [4]. After an initial phase of tests involving computation of some of the redox potentials of HO* and O2 (steps of the Latimer diagram of O2) we continue with the study of a number of model reactions between these radicals and organic molecules forming stable radicals such as the ascorbate anion, (simple) quinones, and tyrosine. One of the issues we will study is the coupling to proton transfers the role of long range electron transfer in the mechanism.


1. "Density functional molecular dynamics study of the redox reactions of two anionic aqueous transition metal complexes."
Y. Tateyama, J. Blumberger, M. Sprik, I. Tavernelli, J. Chem. Phys. 122, 234505 (2005) [online link]
2. "Quantum versus classical electron transfer energy as reaction coordinate for the aqueous Ru2+/Ru3+ redox reaction."
J. Blumberger, M. Sprik, Theor. Chem. Acc. (On line first) [online link]
3. "Density functional theory study of tetrathiafulvalene and thianthrene in acetonitrile: structure, dynamics and redox properties".
J. VandeVondele, R. Lynden-Bell, E. J. Meijer, M. Sprik, J. Phys. Chem. B (asap aticle) [online link]
4. "A molecular dynamics study of the hydroxyl radical in solution applying self-interaction corrected density functional methods"
J. VandeVondele, M. Sprik, Phys. Chem. Chem. Phys. 7, 1363 (2005) [online link]

Candidates should have, or be about to receive, an honours degree (at least II.1 or equivalent) in Chemistry or Physics. Experience with computer simulations is helpful, but not required. Full funding (fees and maintenance) for 42 months is available for UK citizens. EU citizens also qualify for full funding provided they hold a degree from a UK university (funding is partial when the degree was obtained elsewhere). The studentship is not available to citizens of non-EU countries. Appointments must be made by 31 March 2006, so applications should be submitted well ahead of this date.
Applications should include a full CV (two copies) and the names of two referees, and should be sent to:

Professor Michiel Sprik
Department of Chemistry
Lensfield Rd
Cambridge CB2 1EW
UK

Informal enquiries may also be made to
Professor Sprik (tel:+44-(0)1223-336314, ms284[at]cam.ac.uk (replace[at] by @)
(see also the department webpage: www.ch.cam.ac.uk)



2. EST PhD Studentship from October 2006 (closed)

REDOX PROPERTIES ORGANO-METALLIC COMPLEXES

Organo-metallic coordination complexes catalyze a variety of organic reactions. Their potential as catalysts depends to a large extent on tuning of the energy levels of the central metal atom by the chemical nature and geometrical arrangement of the ligands. Also solvent effects can play a role. The coupling of electronic structure and ligand geometry can be studied by physical probes such as spectroscopy. Also the redox properties of the complex can be used for this purpose, in particular when analyzed from the perspective of the Marcus theory of electron transfer. A key quantity in this theory is the response of the system to vertical ionization, such as quantified in the reorganization energy. Also the dynamical fluctuations of the vertical energy gaps in reduced and oxidized state contain information that can be used to understand the interaction between electronic structure and atom motion. The Density Functional Theory (DFT) based Molecular Dynamics (gCar-Parrinelloh) method is particularly suitable for such a study because the vertical energy gaps and their dynamics are directly accessible by this computational approach. The idea of the proposed project is to perform such an investigation on a number of model organic-complexes with known catalytic function to see how the redox properties correlate with the catalytic process. The project is a collaboration with Evert Jan Meijer of the University of Amsterdam.

Candidates should have, or be about to receive, an honours degree (at least II.1 or equivalent) in Chemistry or Physics. Experience with computer simulations is helpful, but not required. The studentship is part of the Eurosim program funded by a Marie Curie Early Stage Training (EST) grant. The studentship is not available to UK citizens. Applications must be submitted via the website of the program www.mc-eurosim.cecam.org where further information and instructions can be found.

Informal enquiries may also be made to
Professor Sprik (tel:+44-(0)1223-336314, ms284[at]cam.ac.uk (replace[at] by @)